Display apparatus

ABSTRACT

A display apparatus capable of reducing a defect rate during manufacturing and utilizing thereof, the display apparatus includes a substrate comprising a display area and a peripheral area outside the display area; a display unit over an upper surface of the substrate to correspond to the display area; and a protective film including a protective film base and an adhesive layer, the protective film being attached to the lower surface of the substrate by the adhesive layer, wherein the protective film base includes a first protective film base corresponding at least to the display area, and a second protective film base having physical properties that are different from physical properties of the first protective film base and corresponding to at least a part of the peripheral area.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2016-0068856, filed on Jun. 2, 2016, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND 1. Field

One or more embodiments relate to a display apparatus, and moreparticularly, to a display apparatus having a reduced defective ratioduring manufacturing processes and utilization thereof.

2. Description of the Related Art

In general, a display apparatus includes a display unit on a substrate.In addition, a protective film is attached to a lower surface of thesubstrate.

However, according to a display apparatus of the prior art, defects mayoccur during manufacturing processes of the display apparatus orutilizing the manufactured display apparatus, or lifespan of the displayapparatus may reduce due to a protective film attached to a lowersurface of the substrate.

SUMMARY

One or more embodiments include a display apparatus having a reduceddefective rate during manufacturing and utilizing the display apparatus.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to one or more embodiments, a display apparatus includes: asubstrate including a display area and a peripheral area outside thedisplay area; a display unit over an upper surface of the substrate tocorrespond to the display area; and a protective film including aprotective film base and an adhesive layer, the protective film beingattached to the lower surface of the substrate by the adhesive layer,wherein the protective film base includes a first protective film basecorresponding at least to the display area, and a second protective filmbase having physical properties that are different from physicalproperties of the first protective film base and corresponding to atleast a part of the peripheral area.

The second protective film base may have a light transmittance that isgreater than a light transmittance of the first protective film base.

The first protective film base may have a thermal resistance that isgreater than a thermal resistance of the second protective film base.The first protective film base may have a heat deformation temperaturethat is higher than a heat deformation temperature of the secondprotective film base.

The display apparatus may further include an electronic device or aprinted circuit board over the upper surface of the substrate so as tocorrespond to an electronic device area included in the peripheral area,wherein the second protective film base may correspond at least to theelectronic device area.

The second protective film base may extend to an edge of the substratefacing away from the display area.

A first end portion of the first protective film base in a direction tothe electronic device area may be in surface-contact with a second endportion of the second protective film base in a direction to the displayarea. The first end portion and the second end portion may correspond toan edge of the display area in the direction to the electronic devicearea. The first end portion and the second end portion may correspond toan edge of the electronic device area in the direction to the displayarea.

A first end portion of the first protective film base in a direction tothe electronic device area may correspond to an edge of the display areain a direction to the electronic device area.

A second end portion of the second protective film base in a directionto the display area may correspond to an edge of the electronic devicearea in a direction to the display area.

A first end portion of the first protective film base in a direction tothe electronic device area may be spaced apart from a second end portionof the second protective film base in a direction to the display area.The adhesive layer may include a first adhesive layer corresponding tothe first protective film base and a second adhesive layer correspondingto the second protective film base, and an end portion of the firstadhesive layer in the direction to the electronic device area may bespaced apart from an end portion of the second adhesive layer in thedirection to the display area.

The adhesive layer may include a first adhesive layer corresponding tothe first protective film base and a second adhesive layer having aphysical property different from a physical property of the firstadhesive layer and corresponding to the second protective film base.

The peripheral area may include a bending area and the substrate is bentat the bending area. The first protective film base may correspond tothe bending area.

A part of the first protective film base corresponding to the bendingarea may be at least partially removed.

A part of the first protective film base corresponding to the bendingarea may include a plurality of openings or a plurality of grooves.

Each of the plurality of openings or each of the plurality of groovesmay extend from the display area toward the peripheral area in a virtualcurved surface that is in parallel with the upper surface of thesubstrate that is bent. From among the plurality of openings or theplurality of grooves, openings or grooves locating at a center portionof the bending area may have areas that are greater than areas ofopenings or grooves locating near edges of the bending area.

Inner side surfaces of the plurality of openings or the plurality ofgrooves may be non-perpendicular to the upper surface of the substrate.

A portion of the first protective film base, wherein the portionincludes the plurality of openings or the plurality of grooves, may havean area that is less than an area of the bending area. A portion of thefirst protective film base, wherein the portion may include theplurality of openings or the plurality of grooves, may have an area thatis equal to an area of the bending area. A portion of the firstprotective film base, wherein the portion includes the plurality ofopenings or the plurality of grooves, may have an area that is greaterthan an area of the bending area.

The second protective film base may correspond to the bending area andan adjacent portion to the bending area.

A part of the second protective film base corresponding to the bendingarea may be at least partially removed.

A part of the second protective film base corresponding to the bendingarea may include a plurality of openings or a plurality of grooves. Eachof the plurality of openings or each of the plurality of grooves mayextend from the display area toward the peripheral area in a virtualcurved surface that is in parallel with the upper surface of thesubstrate that is bent. From among the plurality of openings or theplurality of grooves, openings or grooves locating at a center portionof the bending area may have areas that are greater than areas ofopenings or grooves locating near edges of the bending area.

The adhesive layer may include an opening corresponding to the bendingarea. The opening may be filled with air. The protective film base mayinclude an opening corresponding to the opening of the adhesive layer.

The adhesive layer may include a plurality of openings corresponding tothe bending area. The first protective film base may correspond to thebending area, and the first protective film base may include a pluralityof openings or a plurality of grooves corresponding to the plurality ofopenings of the adhesive layer. The second protective film base maycorrespond to the bending area and an adjacent portion to the bendingarea, and the second protective film base may include a plurality ofopenings or a plurality of grooves corresponding to the plurality ofopenings of the adhesive layer.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 2 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 3 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 4 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 5 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 6 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 7 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 8 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 9 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 10 is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment;

FIG. 11 is a schematic perspective view of a part of a display apparatusaccording to an embodiment;

FIG. 12 is a schematic cross-sectional view of a modified example of thepart of FIG. 11;

FIG. 13 is a schematic plan view of a part of a protective film includedin a display apparatus according to an embodiment;

FIG. 14 is a schematic plan view of a part of a protective film includedin a display apparatus according to an embodiment;

FIG. 15 is a schematic plan view of a part of a protective film includedin a display apparatus according to an embodiment;

FIG. 16 is a schematic plan view of a part of a protective film includedin a display apparatus according to an embodiment;

FIG. 17 is a schematic plan view of a part of a protective film includedin a display apparatus according to an embodiment;

FIG. 18 is a schematic plan view of a part of a protective film includedin a display apparatus according to an embodiment;

FIG. 19 is a schematic cross-sectional view of the display apparatustaken along a line XIX-XIX of FIG. 13;

FIG. 20 is a schematic cross-sectional view of a modified part of adisplay apparatus according to an embodiment; and

FIG. 21 is a schematic cross-sectional view of a modified part of adisplay apparatus according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the present description. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items. Expressions such as “at least one of,” whenpreceding a list of elements, modify the entire list of elements and donot modify the individual elements of the list.

Hereinafter, the present disclosure will be described in detail byexplaining example embodiments of the inventive concept with referenceto the attached drawings. Like reference numerals in the drawings denotelike elements.

Sizes of components in the drawings may be exaggerated for convenienceof explanation. In other words, since sizes and thicknesses ofcomponents in the drawings are arbitrarily illustrated for convenienceof explanation, the following embodiments are not limited thereto.

In the following examples, the x-axis, the y-axis and the z-axis are notlimited to three axes of the rectangular coordinate system, and may beinterpreted in a broader sense. For example, the x-axis, the y-axis, andthe z-axis may be perpendicular to one another, or may representdifferent directions that are not perpendicular to one another.

FIG. 1 is a schematic cross-sectional view of a display apparatusaccording to an embodiment. As shown in FIG. 1, the display apparatusaccording to the embodiment includes a substrate 100, a display unit DU,and a protective film 170.

The substrate 100 includes a display area DA and a peripheral area PAoutside the display area DA. The substrate 100 may include variousmaterials having flexible or bendable characteristics, e.g., polymerresins such as polyethersulphone (PES), polyacrylate (PAR),polyetherimide (PEI), polyethylene naphthalate (PEN), polyethyleneterephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polyimide(PI), polycarbonate (PC), and cellulose acetate propionate (CAP). Inaddition, the substrate 100 may include a multi-layered structure insome embodiments.

The display unit DU is over an upper surface of the substrate (in the +zdirection) so as to correspond to the display area DA. The display unitDU may include a display device such as an organic light-emitting deviceor a thin film transistor. Exemplary configurations of the display unitDU will be described with reference to later described embodiments.

The protective film 170 includes a protective film base 171 and anadhesive layer 172. The protective film 170 is attached to a lowersurface of the substrate 100 (in −z direction) via the adhesive layer172. That is, the protective film 170 is on a lower surface of thesubstrate 100 opposite (−z direction) to the display unit DU (+zdirection). The adhesive layer 172 of the protective film 170 mayinclude, for example, a pressure sensitive adhesive (PSA).

The protective film base 171 included in the protective film 170 withthe adhesive layer 172 may include a first protective film base 171 aand a second protective film base 171 b. The first protective film base171 a and the second protective film base 171 b may be at the same planeas each other. In addition, as shown in FIG. 1, the first protectivefilm base 171 a may correspond at least to the display area DA, and thesecond protective film base 171 b may correspond at least to a part ofthe peripheral area PA. That is, the first protective film base 171 amay have an area that is equal to or greater than that of the displayarea DA. In FIG. 1, the first protective film base 171 a is shown tocorrespond to a part of the peripheral area PA, which is adjacent to thedisplay area DA, as well as the display area DA.

In the protective film base 171 as above, the first protective film base171 a and the second protective film base 171 b may have physicalproperties different from each other. In detail, a light transmittanceof the second protective film base 171 b may be greater than that of thefirst protective film base 171 a. Also, a thermal resistance of thefirst protective film base 171 a may be higher than that of the secondprotective film base 171 b. In more detail, a heat deformationtemperature, at which deformation occurs, of the first protective filmbase 171 a may be higher than that of the second protective film base171 b.

As shown in FIG. 1, the display apparatus may further include anelectronic device 800 such as a driver integrated circuit (IC). Theelectronic device 800 is on the peripheral area PA of the substrate 100.In detail, the electronic device 800 is arranged over the upper surfaceof the substrate 100 (in the +z direction) so as to correspond to anelectronic device area (EDA) included in the peripheral area PA of thesubstrate 100. In FIG. 1, wires and/or pads over the upper surface ofthe substrate 100 (in the +z direction) are not shown for convenience ofdescription, and the electronic device 800 may be electrically connectedto the wires and/or pads that are not shown.

The electronic device 800 is attached onto the substrate 100 by ananisotropic conductive film (ACF). That is, conductive balls 700included in the ACF contact the wires and/or pads on the substrate 100,and at the same time, contact bumps 810 are disposed under a body 820 ofthe electronic device 800 so as to electrically connect the wires and/orpads to the bumps 810. Accordingly, the electronic device 800 may beelectrically connected to the wires and/or pads. Here, to check whetherthe electronic device 800 is electrically connected to the wires and/orpads, a pressure mark test may be performed. If the electronic device800 is not properly connected to the wires and/or pads, this may causedefects in the display apparatus.

The pressure mark test may check, for example, a degree of brokenconductive balls 700 due to a pressure applied when the electronicdevice 800 is mounted on the substrate 100. Breaking of the conductiveballs 700 may denote that the conductive balls 700 are interposedbetween the bumps 810 of the electronic device 800 and the wires and/orpads on the substrate 100 and pressurized, and accordingly, it may beestimated that the electronic device 800 is electrically connected tothe wires and/or pads on the substrate 100.

To perform the pressure mark test, a portion of the protective film 170corresponding to the electronic device 800 may have a light transmittingproperty. That is, the protective film 170 has the portion having hightransmittance correspond to the electronic device 800, so that status ofthe conductive balls 700 may be identified through the protective film170 and the substrate 100. To do this, the second protective film base171 b, which corresponds at least to the electronic device area EDA onwhich the electronic device 800 is located, may be set to have hightransmittance. Therefore, when the light transmittance of the secondprotective film base 171 b is greater than that of the first protectivefilm base 171 a, and the substrate 100 also has the light transmittingproperty, the pressure mark test may be performed to determine whetherthe electronic device 800 is properly connected to the wires and/or padson the substrate 100.

In addition, the display apparatus may undergo various reliability testsduring manufacturing processes thereof. This is for evaluating, inadvance during the manufacturing of the display apparatus, whether therewould be problems when the display apparatus is used under variouscircumstances after being manufactured. The reliability tests mayinclude, for example, evaluating whether the display apparatus isdefective under a high temperature or whether the display apparatus isdefective under a humid circumstance. Therefore, individual property ofelements in the display apparatus may need to be maintained during thetests under the high temperature or the humid circumstance. Inparticular, if the display apparatus has a flexible property or abendable property at the display area DA, degradation of the flexible orbendable property may need to be evaluated in the reliability tests.

To do this, a thermal resistance of the first protective film base 171 athat corresponds to the display area DA may be improved. Therefore, thethermal resistance of the first protective film base 171 a may begreater than that of the second protective film base 171 b. In detail,the heat deformation temperature, at which deformation occurs, of thefirst protective film base 171 a may be higher than that of the secondprotective film base 171 b. As such, the portion of the protective film170 that corresponds to the display area DA may not be deformed duringthe reliability tests.

Since the second protective film base 171 b corresponds to an outerportion of the display area DA, even when the second protective filmbase 171 b and flexibility of the second protective film base 171 bdegrades during the reliability tests, the flexible or bendable propertyof the display area DA may not degrade. Therefore, a user observing thedisplay area DA would recognize the entire flexible or bendable propertyof the display apparatus as being maintained.

The protective film base 171 of the protective film 170 may includepolyimide and polyethylene. In particular, the first protective filmbase 171 a may include polyimide, and the second protective film base171 b may include polyethylene. Polyethylene generally has a higherlight transmittance than that of polyimide. Therefore, the secondprotective film base 171 b including polyethylene may have a higherlight transmittance than that of the first protective film base 171 aincluding polyimide. In addition, a heat deformation temperature ofpolyethylene is about 80° C., and a heat deformation temperature ofpolyimide is much higher than 80° C. Therefore, the first protectivefilm base 171 a including polyimide has a greater thermal resistancethan that of the second protective film base 171 b includingpolyethylene.

According to an embodiment, the protective film 170 covers the lowersurface of the substrate 100 (in the −z direction) as much as possibleso as to sufficiently protect the lower surface of the substrate 100 (inthe −z direction). Therefore, as shown in FIG. 1, the second protectivefilm base 171 b may extend to an edge of the substrate 100 facing awayfrom the display area DA (+x direction). In FIG. 1, an end surface ofthe substrate 100 in opposite direction to the display area DA flusheswith an end surface of the second protective film base 171 b.

In addition, as shown in FIG. 1, a first end portion of the firstprotective film base 171 a in a direction toward the electronic devicearea EDA (+x direction) may surface-contact a second end portion of thesecond protective film base 171 b in a direction toward the display areaDA (−x direction). As such, the protective film 170 may mostly protectthe lower surface of the substrate 100. In this case, the first endportion and the second end portion may be located in the peripheral areaPA as shown in FIG. 1, but are not limited thereto. That is, as shown inFIG. 2, which is a schematic cross-sectional view of a part of a displayapparatus according to an embodiment, the first end portion and thesecond end portion may be located at a boundary between the display areaDA and the peripheral area PA. In this case, the first end portion andthe second end portion correspond to an edge of the display area DA in adirection toward the electronic device area EDA. In addition, FIG. 2shows that the display area DA has an area greater than that of thedisplay unit DU. In the case of FIG. 3, which is a schematiccross-sectional view of a part of a display apparatus according to anembodiment, an edge of the display area corresponds to an edge of thedisplay unit DU, the first end portion and the second end portion mayalso be located at a boundary between the display area DA and theperipheral area PA.

The second protective film base 171 b having high light transmittancemay correspond at least to the electronic device area EDA. Therefore, asshown in FIG. 4, which is a schematic cross-sectional view of a part ofa display apparatus according to an embodiment, the first end portionand the second end portion may correspond to an edge of the electronicdevice area EDA in a direction toward the display area DA (−xdirection). In this case, the pressure mark test for checking themounting status of the electronic device 800 may be sufficientlyperformed via the second protective film base 171 b having excellentlight transmittance, and at the same time, the lower surface of thesubstrate 100 (in the −z direction) may be protected as much as possibleby the first protective film base 171 a having excellent thermalresistance.

So far, the case in which the display apparatus includes the electronicdevice 800 is described as above, but one or more embodiments are notlimited thereto. For example, as shown in FIG. 5, which is a schematiccross-sectional view of a part of a display apparatus according to anembodiment, the display apparatus may include a printed circuit board900. The printed circuit board 900 is also attached onto the substrate100 via an anisotropic conductive film. That is, the conductive balls700 of the anisotropic conductive film contact the wires and/or pads(not shown) on the substrate 100, and at the same time, contact bumps910 on a lower portion of a body 920 of the printed circuit board 900,so as to electrically connect the wires and/or pads to the bumps 910.Accordingly, the printed circuit board 900 may be electrically connectedto the wires and/or pads.

In this case, the pressure mark test may also be performed to checkwhether the printed circuit board 900 is electrically connected to thewires and/or pads. To do this, at least the second protective film base171 b may correspond to the electronic device area EDA in which theprinted circuit board 900 is located, and a portion of the protectivefilm 170, which corresponds to the electronic device area EDA, that is,the second protective film base 171 b may have excellent lighttransmittance. Therefore, the light transmittance of the secondprotective film base 171 b may be greater than that of the firstprotective film base 171 a. The printed circuit board 900 may extend tooutside the substrate 100. Therefore, explaining that the printedcircuit board 900 is located in the electronic device area EDA may beunderstood as explaining that a portion of the printed circuit board900, which is electrically connected to the substrate 100, is located inthe electronic device area EDA.

The display apparatus according to the embodiment of FIG. 5 may be alsomodified as described above with reference to FIGS. 2 to 4. That is, thefirst end portion of the first protective film base 171 a in thedirection toward the electronic device area EDA (+x direction) and thesecond end portion of the second protective film base 171 b in thedirection toward the display area DA (−x direction) may contact eachother by surfaces, and the first and second end portions may be locatedat the boundary between the display area DA and the peripheral area PAas shown in FIG. 2. In addition, in FIG. 5, the display area DA is shownto have an area greater than that of the display unit DU. However, anedge of the display area DA may correspond to an edge of the displayunit DU, and the first and second end portions may be located at theboundary between the display area DA and the peripheral area PA as shownin FIG. 3. The second protective film base 171 b having an excellentlight transmittance may correspond at least to the electronic devicearea EDA. Therefore, like the example shown in FIG. 4, the first andsecond end portions may correspond to the edge of the electronic devicearea EDA in the direction toward the display area DA (−x direction).

The display apparatus may include both the electronic device 800 and theprinted circuit board 900, and in this case, the electronic device 800and the printed circuit board 900 may be located in the electronicdevice area EDA. Here, that the printed circuit board 900 is located inthe electronic device area EDA may denote that a portion of the printedcircuit board 900, which is electrically connected to the substrate 100,is located in the electronic device area EDA.

The case in which the protective film base 171 includes the first andsecond protective film bases 171 a and 171 b is described as above, butone or more embodiments are not limited thereto. For example, as shownin FIG. 6 that is a schematic cross-sectional view of a part of adisplay apparatus according to an embodiment, the adhesive layer 172 mayalso include a first adhesive layer 172 a and a second adhesive layer172 b. In this case, the first adhesive layer 172 a may correspond tothe first protective film base 171 a, and the second adhesive layer 172b may correspond to the second protective film base 171 b. In addition,the first adhesive layer 172 a and the second adhesive layer 172 b mayhave different physical properties from each other.

For example, a light transmittance of the second adhesive layer 172 bmay be greater than that of the first adhesive layer 172 a. Also, athermal resistance of the first adhesive layer 172 a may be greater thanthat of the second adhesive layer 172 b. In more detail, a heatdeformation temperature of the first adhesive layer 172 a, at whichdeformation occurs, may be higher than that of the second adhesive layer172 b. This may be applied to the above-described embodiments andmodified examples thereof, and also, to embodiments that will bedescribed later and modified examples thereof.

In addition, in FIGS. 1 to 6, the first end portion of the firstprotective film base 171 a in the direction toward the electronic devicearea EDA (+x direction) and the second end portion of the secondprotective film base 171 b in the direction toward the display area DA(−x direction) are shown to contact each other by surfaces, but are notlimited thereto. As shown in FIG. 7, which is a schematiccross-sectional view of a part of a display apparatus according to anembodiment, the first protective film base 171 a and the secondprotective film base 171 b may be spaced apart from each other on atleast a part. That is, the first end portion of the first protectivefilm base 171 a in the direction toward the electronic device area EDA(+x direction) and the second end portion of the second protective filmbase 171 b in the direction toward the display area DA may be spacedapart from each other. In this case, the first end portion of the firstprotective film base 171 a in the direction toward the second protectivefilm base 171 b may be located in the peripheral area PA, or at theboundary between the display area DA and the peripheral area PA. Assuch, the lower surface of the substrate 100 (in the −z direction) inthe display area DA may be protected by the first protective film base171 a.

In addition, in FIG. 7, the display area DA is shown to have a greaterarea than that of the display unit DU. However, as shown in FIG. 8,which is a schematic cross-sectional view of a part of a displayapparatus, an edge of the display area DA may correspond to an edge ofthe display unit DU. Also, according to an embodiment, the first endportion may be located at a boundary between the display area DA and theperipheral area PA.

The second protective film base 171 b having the higher lighttransmittance may correspond at least to the electronic device area EDA.As shown in FIG. 9, which is a schematic cross-sectional view of a partof a display apparatus according to an embodiment, the first end portionmay be located in the peripheral area PA and the second end portion maycorrespond to an edge of the electronic device area EDA in the directiontoward the display area DA (−x direction). In this case, the pressuremark test for checking a mounting status of the electronic device 800may be sufficiently performed through the second protective film base171 b having the excellent light transmittance, and at the same time,the lower surface of the substrate 100 (in the −z direction) may beprotected as much as possible by the first protective film base 171 ahaving the excellent thermal resistance.

FIGS. 7 to 9 show that the first protective film base 171 a and thesecond protective film base 171 b of the protective film base 171 arespaced apart from each other on at least some parts thereof. As shown inFIG. 10, which is a schematic cross-sectional view of a part of adisplay apparatus according to an embodiment, the adhesive layer 172 mayalso include the first adhesive layer 172 a and the second adhesivelayer 172 b, wherein the first adhesive layer 172 a and the secondadhesive layer 172 b may be spaced apart from each other on at leastsome parts thereof.

That is, the first end portion of the first protective film base 171 ain the direction toward the electronic device area EDA (+x direction)and the second end portion of the second protective film base 171 b inthe direction toward the display area DA (−x direction) may be spacedapart from each other, and an end portion of the first adhesive layer172 a corresponding to the first protective film base 171 a in thedirection toward the electronic device area EDA and an end portion ofthe second adhesive layer 172 b corresponding to the second protectivefilm base 171 b in the direction toward the display area DA may bespaced apart from each other.

The display apparatus having the substrate 100 of a flat state isdescribed as above, but is not limited thereto. Referring to FIG. 11,which is a schematic perspective view of a part of a display apparatusaccording to an embodiment, a part of the display apparatus, that is, apart of the substrate 100, may be bent, so that the display apparatusmay also have a partially bent shape like the substrate 100.

As shown in FIG. 11, the substrate 100 of the display apparatusaccording to the embodiment includes a bending area BA extending in afirst direction (+y direction). The bending area BA is located between afirst area 1A and a second area 2A in a second direction (+x direction)crossing the first direction. The first area 1A may include at least thedisplay area DA as described above. The substrate 100 is bent about abending axis BAX that extends in the first direction (+y direction) asshown in FIG. 1.

FIG. 12 is a schematic cross-sectional view of a modified part of thedisplay apparatus of FIG. 11. As described above, the substrate 100 isbent at the bending area BA, but is shown not to be bent in FIG. 12 forconvenience of description. This will be applied to embodiments thatwill be described later and modified examples thereof.

As shown in FIG. 12, the first area 1A of the substrate 100 includes thedisplay area DA. The first area 1A may further include a part of theperipheral area PA outside the display area DA, in addition to thedisplay area DA, as shown in FIG. 12. The second area 2A also includesthe peripheral area PA. The display unit DU (see FIG. 1) including adisplay device, such as an organic light-emitting device 300, and a thinfilm transistor 210 may be located in the first area 1A. The displayunit DU may only include components arranged in the display area DA, ormay include components that are included in the first area 1A andarranged in the peripheral area PA. The substrate 100 has the bendingarea BA between the first area 1A and the second area 2A, and is bent atthe bending area BA to have the shape shown in FIG. 11.

In the display area DA, the thin film transistor 210 to which theorganic light-emitting device 300 is electrically connected may be inthe display area DA, in addition to the display device such as theorganic light-emitting device 300. Electric connection of the organiclight-emitting device 300 to the thin film transistor 210 may beunderstood to be that a pixel electrode 310 is electrically connected tothe thin film transistor 210. In some embodiments, a thin filmtransistor (not shown) may also be on a peripheral area outside thedisplay area DA of the substrate 100. The thin film transistor on theperipheral area may be, for example, a part of a circuit unit forcontrolling electric signals that are applied to the display area DA.

The thin film transistor 210 may include a semiconductor layer 211including amorphous silicon, polycrystalline silicon, or an organicsemiconductor material, a gate electrode 213, a source electrode 215 a,and a drain electrode 215 b. To ensure insulation between thesemiconductor layer 211 and the gate electrode 213, a gate insulatinglayer 120 may be between the semiconductor layer 211 and the gateelectrode 213, wherein the gate insulating layer 120 includes aninorganic material such as silicon oxide, silicon nitride, and/orsilicon oxynitride. In addition, an interlayer insulating layer 130 maybe on the gate electrode 213, and a source electrode 215 a and a drainelectrode 215 b may be on the interlayer insulating layer 130, whereinthe interlayer insulating layer 130 includes an inorganic material suchas silicon oxide, silicon nitride, and/or silicon oxynitride. Theinsulating layers including the inorganic material may be formed bychemical vapor deposition (CVD) or atomic layer deposition (ALD). Thiswill be applied to other embodiments and modifications thereof that willbe described later.

A buffer layer 110 may be between the thin film transistor 210 havingthe above structure and the substrate 100. The buffer layer 110 mayinclude an inorganic material such as silicon oxide, silicon nitride,and/or silicon oxynitride. The buffer layer 110 may improve smoothnessof the upper surface of the substrate 100, or prevent or reduceinfiltration of impurities from the substrate 100 into the semiconductorlayer 211 of the thin film transistor 210.

A planarization layer 140 may be arranged on the thin film transistor210. For example, as shown in FIG. 12, when the organic light-emittingdevice 300 is arranged on the thin film transistor 210, theplanarization layer 140 may planarize an upper portion of a protectivelayer covering the thin film transistor 210. The planarization layer 140may include, for example, an organic material such as acryl,benzocyclobutene (BCB), and hexamethyldisiloxane (HMDSO). In FIG. 12,although the planarization layer 140 has a single-layered structure, theplanarization layer 140 may be variously modified; for example, theplanarization layer 140 may have a multi-layered structure. In addition,as shown in FIG. 12, the planarization layer 140 may have an openingoutside the display area DA, such that a part of the planarization layer140 in the display area DA and a part of the planarization layer 140 inthe second area 2A may be physically separate from each other. Thus,impurities from outside may not reach the display area DA via theplanarization layer 140.

In the display area DA, the organic light-emitting device 300 may be onthe planarization layer 140. The organic light-emitting device 300includes the pixel electrode 310, an opposite electrode 330, and anintermediate layer 320 between the pixel electrode 310 and the oppositeelectrode 330 and including an emission layer. The pixel electrode 310may contact one of the source electrode 215 a and the drain electrode215 b via an opening formed in the planarization layer 140 and beelectrically connected to the thin film transistor 210, as shown in FIG.12.

A pixel defining layer 150 may be on the planarization layer 140. Thepixel defining layer 150 includes openings corresponding respectively tosub-pixels, that is, at least an opening exposing a center portion ofthe pixel electrode 310, to define pixels. Also, in the example shown inFIG. 12, the pixel defining layer 150 increases a distance between anedge of the pixel electrode 310 and the opposite electrode 330 above thepixel electrode 310 so as to prevent an arc from generating at the edgeof the pixel electrode 310. The pixel defining layer 150 may include anorganic material, for example, PI or HMDSO.

The intermediate layer 320 of the organic light-emitting device mayinclude low-molecular weight organic materials or polymer materials.When the intermediate layer 320 includes a low-molecular weight organicmaterial, the emission layer may include a hole injection layer (HIL), ahole transport layer (HTL), an emission layer (EML), an electrontransport layer (ETL), and an electron injection layer (EIL) in a singleor multiple-layered structure, and examples of organic materials mayinclude copper phthalocyanine (CuPc),N,N′-Di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), andtris-8-hydroxyquinoline aluminum (Alq₃). The low-molecular weightorganic materials may be deposited by a vacuum deposition method.

When the intermediate layer 320 includes a polymer material, theintermediate layer 320 may include an HTL and an EML. Here, the HTL mayinclude PEDOT, and the EML may include a poly-phenylenevinylene(PPV)-based or polyfluorene-based polymer material. The intermediatelayer 320 above may be formed by a screen printing method, an inkjetprinting method, or a laser induced thermal imaging (LITI) method.

However, the intermediate layer 320 is not limited to the above example,and may have various structures. In addition, the intermediate layer 320may include a layer that is integrally formed throughout a plurality ofpixel electrodes 310, or a layer that is patterned to correspond to eachof the plurality of pixel electrodes 310.

The opposite electrode 330 is arranged above the display area DA, and asshown in FIG. 12, may cover the display area DA. That is, the oppositeelectrode 330 may be integrally formed with respect to a plurality oforganic light-emitting devices, so as to correspond to a plurality ofpixel electrodes 310.

Since the organic light-emitting device 300 may be easily damaged byexternal moisture or oxygen, an encapsulation layer 400 may cover theorganic light-emitting device 300 to protect the organic light-emittingdevice. The encapsulation layer 400 covers the display area DA, and mayalso extend outside the display area DA. The encapsulation layer 400 mayinclude a first inorganic encapsulation layer 410, an organicencapsulation layer 420, and a second inorganic encapsulation layer 430,as shown in FIG. 12.

The first inorganic encapsulation layer 410 covers the oppositeelectrode 330, and may include silicon oxide, silicon nitride, and/orsilicon oxynitride. In some embodiments, other layers such as a cappinglayer may be arranged between the first inorganic encapsulation layer410 and the opposite electrode 330. Since the first inorganicencapsulation layer 410 is formed according to a structure thereunder,the first inorganic encapsulation layer 410 may have an uneven uppersurface as shown in FIG. 12. The organic encapsulation layer 420 coversthe first inorganic encapsulation layer 410, and unlike the firstinorganic encapsulation layer 410, the organic encapsulation layer 420may have an even upper surface. In more detail, the organicencapsulation layer 420 may substantially have an even upper surface ata portion corresponding to the display area DA. The organicencapsulation layer 420 may include at least one material selected fromthe group consisting of PET, PEN, PC, PI, polyethylene sulfonate,polyoxymethylene, polyarylate, and hexamethyldisiloxane. The secondinorganic encapsulation layer 430 covers the organic encapsulation layer420, and may include silicon oxide, silicon nitride, and/or siliconoxynitride. The second inorganic encapsulation layer 430 may contact thefirst inorganic encapsulation layer 410 at an edge thereof outside thedisplay area DA, such that the organic encapsulation layer 420 is notexposed to the outside.

As described above, since the encapsulation layer 400 includes the firstinorganic encapsulation layer 410, the organic encapsulation layer 420,and the second inorganic encapsulation layer 430, even if there is acrack in the encapsulation layer 400 in the above multi-layeredstructure, the crack may be disconnected between the first inorganicencapsulation layer 410 and the organic encapsulation layer 420 orbetween the organic encapsulation layer 420 and the second inorganicencapsulation layer 430. As such, forming a path through which externalmoisture or oxygen may infiltrate into the display area DA may beprevented or reduced.

In some embodiments, a touch electrode of various patterns forimplementing a touch screen function or a touch protective layer forprotecting the touch electrode layer may be arranged on theencapsulation layer 400. In addition, a polarization plate 520 may beattached on the encapsulation layer 400 via an optically clear adhesive(OCA) 510. If there is the touch electrode or the touch protective layeron the encapsulation layer 400, the OCA 510 and the polarization plate520 are above the touch electrode or the touch protective layer. Inaddition, a printed circuit board (not shown) or an electronic chip (notshown) may be attached to the second area 2A. In FIG. 12, a part of thesubstrate 100 opposite to the display area DA (that is, +x direction) isomitted. In addition, a bending protection layer (BPL) 600 may be onoutside the display area DA.

The polarization layer 520 may reduce reflection of external light. Forexample, when an external light passing through the polarization plate520 is reflected by an upper surface of the opposite electrode 330 andthen passes through the polarization plate 520 again, the external lightpasses through the polarization plate 520 twice, and a phase of theexternal light may be changed. Therefore, because a phase of reflectedlight is different from the phase of the external light entering thepolarization plate 520, destructive interference occurs, andaccordingly, the reflection of the external light may be reduced, andvisibility may be improved. The OCA 510 and the polarization plate 520may cover an opening in the planarization layer 140, as shown in FIG. 2.The display apparatus according to one or more embodiments may notessentially include the polarization plate 520, and in some embodiments,the polarization plate 520 may be omitted or replaced by other elements.For example, the polarization plate 520 may be omitted, and a blackmatrix and a color filter may be used to reduce reflection of externallight.

In addition, the buffer layer 110, the gate insulating layer 120, andthe interlayer insulating layer 130 including the inorganic material maybe collectively referred to as an inorganic insulating layer. Theinorganic insulating layer may include an opening corresponding to thebending area BA, as shown in FIG. 12. That is, the buffer layer 110, thegate insulating layer 120, and the interlayer insulating layer 130 mayrespectively include openings 110 a, 120 a, and 130 a corresponding tothe bending area BA. That the opening corresponds to the bending area BAmay denote that the opening overlaps with the bending area BA. Here, anarea of the opening may be greater than that of the bending area BA. Todo this, in FIG. 12, a width OW of the opening is greater than that ofthe bending area BA. Here, the area of the opening may be defined as thesmallest area among areas of the openings 110 a, 120 a, and 130 a of thebuffer layer 110, the gate insulating layer 120, and the interlayerinsulating layer 130. In addition, in FIG. 12, the area of the openingis defined by an area of the opening 110 a in the buffer layer 110.

In FIG. 12, although an inner side surface of the opening 110 a of thebuffer layer 110 and an inner side surface of the opening 120 a in thegate insulating layer 120 correspond to each other, one or moreembodiments are not limited thereto. For example, an area of the opening120 a of the gate insulating layer 120 may be greater than that of theopening 110 a in the buffer layer 110. In this case, the area of theopening may be also defined as the smallest area among areas of theopenings 110 a, 120 a, and 130 a of the buffer layer 110, the gateinsulating layer 120, and the interlayer insulating layer 130.

The display apparatus according to the embodiment of FIG. 12 includes anorganic material layer 160 that fills at least partially the opening inthe inorganic insulating layer. In FIG. 12, the organic material layer160 completely fills the opening. In addition, the display apparatusaccording to the embodiment includes a first conductive layer 215 c thatextends from the first area 1A to the second area 2A through the bendingarea BA and is above the organic material layer 160. The firstconductive layer 215 c may be on the inorganic insulating layer such asthe interlayer insulating layer 130 if the organic material layer 160 isomitted. The first conductive layer 215 c may be formed simultaneouslywith the source electrode 215 a or the drain electrode 215 b by usingthe same material as that of the source electrode 215 a or the drainelectrode 215 b.

As described above, although FIG. 12 shows a state in which the displayapparatus is not bent for convenience of description, the displayapparatus according to the embodiment is actually in a state in whichthe substrate 100 is bent at the bending area BA, as shown in FIG. 11.To do this, the display apparatus is manufactured so that the substrate100 is flat, as shown in FIG. 12, during the manufacturing processes,and after that, the substrate 100 is bent at the bending area BA so thatthe display apparatus may have the shape as shown in FIG. 11. Here,while the substrate 100 is bent at the bending area BA, tensile stressmay be applied to the first conductive layer 215 c. However, in thedisplay apparatus according to the embodiment, the occurrence of defectsin the first conductive layer 215 c during the bending process may beprevented or reduced.

If the inorganic insulating layer including the buffer layer 110, thegate insulating layer 120, and/or the interlayer insulating layer 130does not include the opening corresponding to the bending area BA, butcontinuously extends from the first area 1A to the second area 2A, andif the first conductive layer 215 c is on such above inorganicinsulating layer, large tensile stress is applied to the firstconductive layer 215 c during bending the substrate 100. In particular,since the inorganic insulating layer has a greater hardness than that ofan organic material layer, cracks are likely to form in the inorganicinsulating layer in the bending area BA. When a crack occurs in theinorganic insulating layer, the crack may also occur in the firstconductive layer 215 c on the inorganic insulating layer, and thus, theprobability of generating defects such as disconnection in the firstconductive layer 215 c increases greatly.

However, according to the display apparatus of the embodiment, theinorganic insulating layer includes the opening corresponding to thebending area BA, and the part of the first conductive layer 215 c, whichcorresponds to the bending area BA, is on the organic material layer 160that at least partially fills the opening of the inorganic insulatinglayer. Since the inorganic insulating layer includes the openingcorresponding to the bending area BA, the possibility of cracksoccurring in the inorganic insulating layer is greatly low, and theorganic material layer 160 is less likely to have cracks due tocharacteristics of the organic material. Therefore, the occurrence ofcracks on the organic material layer 160 in the portion of the firstconductive layer 215 c corresponding to the bending area BA may beprevented or reduced. Since the organic material layer 160 has a lowerhardness than that of an inorganic material layer, the organic materiallayer 160 may absorb the tensile stress generated due to the bending ofthe substrate 100 and thereby reduce concentration of the tensile stresson the first conductive layer 215 c.

The display apparatus according to the embodiment may include secondconductive layers 213 a and 213 b, in addition to the first conductivelayer 215 c. The second conductive layers 213 a and 213 b are formed inthe first area 1A or the second area 2A at a layer level different fromthat of the first conductive layer 215 c, and may be electricallyconnected to the first conductive layer 215 c. In FIG. 12, the secondconductive layers 213 a and 213 b may include the same material as thatof the gate electrode 213 of the thin film transistor 210, and be at thesame layer as the gate electrode 213, that is, on the gate insulatinglayer 120. In addition, the first conductive layer 215 c contacts thesecond conductive layers 213 a and 213 b via contact holes formed in theinterlayer insulating layer 130. In addition, the second conductivelayer 213 a is in the first area 1A, and the second conductive layer 213b is in the second area 2A.

The second conductive layer 213 a in the first area 1A may beelectrically connected to the thin film transistor 210 within thedisplay area DA, and accordingly, the first conductive layer 213 c maybe electrically connected to the thin film transistor 210 of the displayarea DA via the second conductive layer 213 a. The second conductivelayer 213 b in the second area 2A may also be electrically connected tothe thin film transistor 210 of the display area DA via the firstconductive layer 215 c. As such, the second conductive layers 213 a and213 b that are outside the display area DA may be electrically connectedto the elements in the display area DA, or may extend toward the displayarea DA so that at least some parts of the second conductive layers 213a and 213 b may be located in the display area DA.

As described above, although FIG. 12 shows a state in which the displayapparatus is not bent for convenience of description, the displayapparatus according to the embodiment is actually in a state in whichthe substrate 100 is bent at the bending area BA, as shown in FIG. 11.To do this, the display apparatus is manufactured so that the substrate100 is flat, as shown in FIG. 12, during the manufacturing processes,and after that, the substrate 100 is bent at the bending area BA so thatthe display apparatus may have the shape as shown in FIG. 11. Here,while the substrate 100 is bent at the bending area BA, tensile stressmay be applied to the elements in the bending area BA.

Therefore, the first conductive layer 215 c crossing over the bendingarea BA includes a material having high elongation rate, so that defectssuch as cracks in the first conductive layer 215 c or disconnection ofthe first conductive layer 215 c may be prevented. In addition, thesecond conductive layers 213 a and 213 b including a material having anelongation rate lower than that of the first conductive layer 215 c, andelectrical/physical characteristics different from those of the firstconductive layer 215 c are formed in the first area 1A or the secondarea 2A, and thus, an efficiency of transferring electric signals in thedisplay apparatus may be improved, or a defect rate during themanufacturing processes of the display apparatus may be reduced. Forexample, the second conductive layers 213 a and 213 b may includemolybdenum, and the first conductive layer 215 c may include aluminum.The first conductive layer 215 c and the second conductive layers 213 aand 213 b may have multi-layered structures, according to someembodiments.

Unlike the example of FIG. 12, at least a part of an upper portion ofthe second conductive layer 213 b in the second area 2A may not becovered by the planarization layer 140, but is exposed to the outside,in order to electrically connect to various electronic devices orprinted circuit boards.

In addition, as shown in FIG. 12, the organic material layer 160 mayhave an uneven surface 160 a in at least a part of an upper surfacethereof in a +z direction. Since the organic material layer 160 includesthe uneven surface 160 a, the first conductive layer 215 c on theorganic material layer 160 may have an upper surface and/or a lowersurface having a shape corresponding to the uneven surface 160 a of theorganic material layer 160.

As described above, since the tensile stress may be applied to the firstconductive layer 215 c when the substrate 100 is bent at the bendingarea BA in the manufacturing processes, when the upper surface and/orthe lower surface of the first conductive layer 215 c has a shapecorresponding to the uneven surface 160 a of the organic material layer160, the amount of tensile stress applied to the first conductive layer215 c may be reduced. That is, the tensile stress generated during thebending process may be reduced via deformation of the shape of theorganic material layer 160 having a relatively smaller hardness. Here,the first conductive layer 215 c having the uneven shape at least beforethe bending process may be transformed to correspond to the shape of theorganic material layer 160, which is deformed due to the bendingprocess, and thus, the occurrence of defects such as disconnection inthe first conductive layer 215 c may be prevented.

Also, since the uneven surface 160 a is formed at least partially in theupper surface of the organic material layer 160 (in the +z direction), asurface area of the upper surface of the organic material layer 160 anda surface area of the upper and lower surfaces of the first conductivelayer 215 c in the opening may be increased. A large surface area of theupper surface of the organic material layer 160 and the upper and lowersurfaces of the first conductive layer 215 c may denote that adeformation margin is large in order to reduce the tensile stress causeddue to the bending of the substrate 100.

Since the first conductive layer 215 c is on the organic material layer160, the lower surface of the first conductive layer 215 c has a shapecorresponding to the uneven surface 160 a of the organic material layer160. However, the upper surface of the first conductive layer 215 c mayhave an uneven surface that has an independent shape from the shape ofthe uneven surface 160 a of the organic material layer 160.

The uneven surface 160 a in the upper surface (in the +z direction) ofthe organic material layer 160 may be formed in various ways. Forexample, a photoresist material may be used when the organic materiallayer 160 is formed, and an exposure amount may vary depending onlocations in the organic material layer 160, the upper surface of whichis flat, by using a slit mask or a half-tone mask so that a certain partmay be etched (removed) more than other parts. Here, the part that isetched more may be a depressed portion in the upper surface of theorganic material layer 160. The method used when manufacturing thedisplay apparatus according to the embodiment is not limited to theabove example. For example, after forming the organic material layer 160having a flat upper surface, certain portions may be removed by a dryetching method, and other various methods may be used.

The organic material layer 160 may have the uneven surface 160 a in theupper surface (in the +z direction) thereof. For example, the organicmaterial layer 160 may include a plurality of grooves in the uppersurface (in the +z direction) thereof, wherein the plurality of groovesextend in the first direction (+y direction). Here, the shape of theupper surface of the first conductive layer 215 c on the organicmaterial layer 160 corresponds to the shape of the upper surface of theorganic material layer 160.

The uneven surface 160 a of the organic material layer 160 may only bewithin the opening of the inorganic insulating layer. In FIG. 12, awidth UEW of the uneven surface 160 a of the organic material layer 160is less than a width OW of the opening of the inorganic insulatinglayer. If the organic material layer 160 has the uneven surface 160 athroughout the inside and outside the opening in the inorganicinsulating layer, the uneven surface 160 a of the organic material layer160 is near the internal surface of the opening 110 a in the bufferlayer 110, the internal surface of the opening 120 a in the gateinsulating layer 120, or the internal surface of the opening 130 a inthe interlayer insulating layer 130. In this case, the organic materiallayer 160 has a relatively smaller thickness on depressed portions thanthat on protruding portions, and thus, when the depressed portions arelocated around the internal surface of the opening 110 a in the bufferlayer 110, the internal surface of the opening 120 a in the gateinsulating layer 120, or the internal surface of the opening 130 a inthe interlayer insulating layer 130, the organic material layer 160 maybe disconnected. Therefore, the uneven surface 160 a of the organicmaterial layer 160 may only be within the opening of the inorganicinsulating layer, and thus, the disconnection of the organic materiallayer 160 around the internal surface of the opening 110 a in the bufferlayer 110, the internal surface of the opening 120 a of the gateinsulating layer 120, or the internal surface of the opening 130 a inthe interlayer insulating layer 130 may be prevented.

As described above, so as not to generate the disconnection in the firstconductive layer 215 c at the bending area BA, the organic materiallayer 160 may have the uneven surface 160 a over the bending area BA.Therefore, an area of the uneven surface 160 a of the organic materiallayer 160 may be greater than that of the bending area BA and smallerthan that of the opening. That is, as shown in FIG. 12, the width UEW ofthe uneven surface 160 a of the organic material layer 160 is greaterthan the width of the bending area BA and less than the width OW of theopening.

If one of the buffer layer 110, the gate insulating layer 120, and theinterlayer insulating layer 130 includes an organic insulating material,the organic material layer 160 may be formed simultaneously with formingof such a layer including the organic insulating material, and moreover,the layer including the organic insulating material may be integrallyformed with the organic material layer 160. The organic insulatingmaterial may include PET, PEN, PC, PI, polyethylene sulfonate,polyoxymethylene, polyarylate, and hexamethyldisiloxane.

In addition, the BPL 600 may be located outside the display area DA.That is, the BPL 600 may be located over the first conductive layer 215c, corresponding at least to the bending area BA.

When a stack structure is bent, there is a stress neutral plane in thestack structure. If there is no BPL 600, when the substrate 100 is bent,excessive tensile stress may be applied to the first conductive layer215 c in the bending area BA, because the location of the firstconductive layer 215 c may not correspond to a stress neutral plane.However, by forming the BPL 600 and adjusting a thickness and a modulusof the BPL 600, a location of the stress neutral plane in the stackstructure including the substrate 100, the first conductive layer 215 c,and the BPL 600 may be adjusted. Therefore, the stress neutral plane maybe adjusted to be around the first conductive layer 215 c via the BPL600, and thus, the tensile stress applied to the first conductive layer215 c may be reduced.

The BPL 600 may extend to an end of the substrate 100 in the displayapparatus, unlike the example of FIG. 12. For example, in the secondarea 2A, the first conductive layer 215 c, the second conductive layer213 b, and/or other conductive layers electrically connected to thefirst and second conductive layers 215 c and 213 b may not be covered atleast partially by the interlayer insulating layer 130 or theplanarization layer 140, but may be electrically connected to variouselectronic devices or printed circuit boards. Accordingly, the firstconductive layer 215 c, the second conductive layer 213 b, and/or theother conductive layers electrically connected to the first and secondconductive layers 215 c and 213 b may have portions that areelectrically connected to the various electronic devices or the printedcircuit boards. Here, the electrically connected portions need to beprotected against external impurities such as external moisture, andthus, the BPL 600 may cover the electrically connected portions so as toperform as a protective layer as well. To do this, the BPL 600 mayextend to, for example, the end of the substrate 100 of the displayapparatus.

In addition, in FIG. 12, although the upper surface of the BPL 600 in adirection toward the display area DA (−x direction) coincides with theupper surface of the polarization plate 520 in the +z direction, one ormore embodiments are not limited thereto. For example, the end of theBPL 600 in the display area DA direction (−x direction) may partiallycover the upper surface at the end of the polarization plate 520. Inanother example, the end of the BPL 600 in the display area DA direction(−x direction) may not contact the polarization plate 520 and/or the OCA510. In the latter case, during or after forming the BPL 600, moving ofgas generated from the BPL 600 in a direction toward the display area DA(−x direction) and degrading the display device 300 such as the organiclight-emitting device 300 may be prevented.

As shown in FIG. 2, if the upper surface of the BPL 600 in a directiontoward the display area DA (−x direction) coincides with the uppersurface of the polarization plate 520 in the +z direction, if the end ofthe BPL 600 in the display area DA direction (−x direction) partiallycovers the upper surface at the end of the polarization plate 520, or ifthe end of the BPL 600 in the display area DA direction (−x direction)contacts the OCA 510, a thickness of the BPL 600 corresponding to thedisplay area DA (−x direction) may be greater than that of the otherportions in the BPL 600. Since a liquid phase material or a paste-typematerial may be applied and hardened to form the BPL 600, a volume ofthe BPL 600 may be reduced through the hardening process. Here, if theportion of the BPL 600 corresponding to the display area DA (−xdirection) is in contact with the polarization plate 520 and/or the OCA510, the portion of the BPL 600 is fixed at the location, and thus, avolume reduction occurs in remaining portion of the BPL 600. Therefore,the thickness of the BPL 600 corresponding to the display area DA (−xdirection) may be greater than that of the other portion in the BPL 600.

In the above description, the buffer layer 110, the gate insulatinglayer 120, and the interlayer insulating layer 130 are described to havethe openings 110 a, 120 a, and 130 a respectively corresponding to thebending area BA, but one or more embodiments are not limited thereto.For example, the buffer layer 110 may be integrally formed throughoutthe first area 1A, the bending area BA, and the second area 2A withoutan opening, and the gate insulating layer 120 and the interlayerinsulating layer 130 may only have the openings 120 a and 130 a. In thiscase, the inorganic insulating layer including the buffer layer 110, thegate insulating layer 120, and the interlayer insulating layer 130 mayhave a groove, not an opening, and the organic material layer 160 may beunderstood to fill the groove of the inorganic insulating layer. Thatis, the opening in the inorganic insulating layer described above may bereplaced with the groove.

The display apparatus according to the embodiment includes theprotective film 170 as well. The protective film 170 includes theprotective film base 171 and the adhesive layer 172, and detailedstructures thereof are described above with reference to FIGS. 1 to 9.

The configurations described above with reference to FIGS. 11 and 12 maybe mostly applied to the other embodiments that will be described laterand modified examples thereof.

If the substrate 100 is bent at the bending area BA, the protective film170 is also bent at the bending area BA. Here, the protective film 170may not be completely bent due to the mechanical strength thereof, orstress caused by the protective film 170 may be applied to the substrateand defects such as a crack may occur in the substrate 100. Therefore,to prevent the above defects, a part of the protective film base 171corresponding to the bending area BA may include a plurality of openingsor a plurality of grooves. When the protective film base 171 includesthe plurality of openings or the plurality of grooves, bending of theprotective film base 171 at the bending area BA may be sufficientlyperformed. Hereinafter, a case in which the protective film base 171includes the plurality of openings will be described below forconvenience of description, but one or more embodiments are not limitedthereto. For example, the protective film base 171 may include theplurality of grooves, instead of the plurality of openings.

In detail, as shown in FIG. 13, which is a schematic plan view of a partof the protective film 170, that is, the protective film base 171, in adisplay apparatus according to an embodiment, the first protective filmbase 171 a may correspond to the bending area BA. That is, the firstprotective film base 171 a may correspond to the bending area BA and apart of the second area 2A, as well as the display area DA. In thiscase, as shown in FIG. 13, the first protective film base 171 a may notcorrespond to the portion corresponding to the electronic device 800,and instead, the second protective film base 171 b corresponds to theelectronic device 800. FIG. 13 also shows a window view area WVA, whichis an area including the display area DA and understood as a lighttransmitting area of a window disposed above the display unit DU forprotecting the display unit DU.

Here, a part of the first protective film base 171 a corresponding tothe bending area BA may include a plurality of openings 171 a′. Thedisplay apparatus according to the embodiment has the substrate 100 andthe protective film base 171 that are bent at the bending area BA, butFIG. 13 shows the protective film base 171 in a flat state forconvenience of description, and this will be applied to otherembodiments that will be described later and modified examples thereof.

A portion P1 in the first protective film base 171 a, in which theplurality of openings 171 a′ are formed, may have an area that is lessthan that of the bending area BA, as shown in FIG. 13, in a case inwhich protecting of the substrate 100 is more important than bending ofthe substrate 100. However, in a case in which the bending of thesubstrate 100 is prior to protecting of the substrate 100, as shown inFIG. 14, which is a schematic plan view of a part of a protective filmin a display apparatus according to an embodiment, the portion P1 of thefirst protective film base 171 a, in which the plurality of openings 171a′ are formed, may have an area that is equal to that of the bendingarea BA. Moreover, as shown in FIG. 15, which is a schematic plan viewof a part of a protective film in a display apparatus according to anembodiment, the portion P1 of the first protective film base 171 a, inwhich the plurality of openings 171 a′ are formed, may have an area thatis greater than that of the bending area BA.

In addition, as shown in FIGS. 13 to 15, the openings 171 a′ of thefirst protective film base 171 a do not extend in a direction in whichthe bending axis extends (y-axis direction), that is, a directionperpendicular to an axis (x-axis direction) connecting the first area 1Ato the second area 2A. When taking into account a cross-section on aplane (yz plane) including the y-axis and being perpendicular to thex-axis within the bending area BA, the first protective film base 171 ahas a discontinuous shape.

If the openings 171 a′ of the first protective film base 171 a extend inthe direction (y-axis direction), in which the bending axis extends, thebending of the first protective film base 171 a may be sufficientlyperformed, but the stress applied to the substrate 100 by the firstprotective film base 171 a may not be uniform within the bending areaBA. This may cause defects such as a crack in the substrate 100. Inaddition, if the BPL 600 does not have a uniform thickness, the crackmay occur in the first conductive layer 215 c within the bending area BAdue to the stress generated by the BPL 600. However, when the openings171 a′ of the first protective film base 171 a do not extend in thedirection (y-axis direction) in which the bending axis extends, thefirst protective film base 171 a may sufficiently support the substrate100 while being bent easily at the bending area BA, and accordingly,influence of the stress caused by the BPL 600 having uneven thickness tothe first conductive layer 215 c or the substrate 100 may be reduced.

Each of the openings 171 a′ of the first protective film base 171 a mayextend from the display area DA toward the peripheral area PA in avirtual curved surface that is in parallel with the upper surface of thebent substrate 100, as shown in FIG. 16, which is a schematic plan viewof a part of the first protective film base 171 a in a display apparatusaccording to an embodiment. Since FIG. 16 shows that the firstprotective film base 171 a is in a flat state for convenience ofdescription, each opening 171 a′ is shown to extend in the x-axisdirection.

As shown in FIG. 17, which is a schematic plan view of a part of thefirst protective film base 171 a in a display apparatus according to anembodiment, each of the plurality of openings 171 a′ may have a circularshape or a shape similar to the circle, and the plurality of openings171 a′ may be arranged in zig-zags. In addition, as shown in FIG. 18,which is a schematic plan view of a part of the first protective filmbase 171 a in a display apparatus according to an embodiment, from amongthe plurality of openings 171 a′ of the first protective film base 171a, the openings 171 a′ located at a center portion of the bending areaBA may each have an area that is greater than that of each of theopenings 171 a′ located near edges of the bending area BA. In the lattercase, the first protective film base 171 a may be easily bent at thecenter portion of the bending area BA, and in other portions in thebending area BA, the first protective film base 171 a′ may be easilybent while sufficiently supporting the substrate 100.

In addition, as shown in FIG. 19, which is a schematic cross-sectionalview of the display apparatus taken along a line XIX-XIX of FIG. 13,inner side surfaces of the plurality of openings 171 a′ may not beperpendicular to the upper surface of the substrate 100 (in the +zdirection).

As described above, although the display apparatus is not shown to be inthe bent state in FIGS. 12 and 13, the display apparatus according tothe embodiment is bent at the bending area BA as shown in FIG. 11. Sincethe protective film base 171 is also bent at the bending area BA, theremay be stress therein even if the plurality of openings 171 a′ areprovided. The stress may cause isolation of the protective film 170 fromthe substrate 100. However, according to the display apparatus of theembodiment, since the inner side surfaces of the plurality of openings171 a′ are not perpendicular to the upper surface of the substrate 100(in the +z direction), an amount of the internal stress may be greatlyreduced. That is, the thickness of the first protective film base 171 ais reduced near the openings 171 a′ of the first protective film base171 a, and thus, the amount of the internal stress in the firstprotective film base 171 a may be greatly reduced.

FIGS. 12 to 19 show that the first protective film base 171 acorresponds to the bending area BA, but one or more embodiments are notlimited thereto. For example, as shown in FIG. 20, which is a schematiccross-sectional view of a modified example of a display apparatusaccording to an embodiment, the second protective film base 171 b maycorrespond to the bending area BA and adjacent portions to the bendingarea BA. In addition, a part of the second protective film base 171 bcorresponding to the bending area BA may include a plurality of openingsor a plurality of grooves. In this case, each of the plurality ofopenings or each of the plurality of grooves may extend from the displayarea DA toward the peripheral area PA in a virtual curved surface thatis in parallel with the upper surface of the bent substrate 100 (similarto the example of FIG. 16). In addition, similarly to the example shownin FIG. 18, from among the plurality of openings or the plurality ofgrooves, the openings or grooves located at the center portion of thebending area BA may each have an area that is greater than that of eachof the openings or grooves near the edges of the bending area BA.

In addition, FIGS. 13 to 19 illustrate that the first protective filmbase 171 a includes the plurality of openings 171 a′, but one or moreembodiments are not limited thereto. For example, the first protectivefilm base 171 a may be at least partially removed corresponding to thebending area BA, so that one opening or one groove corresponding to thebending area BA may be obtained. As shown in FIG. 20, when the secondprotective film base 171 b corresponds to the bending area BA and anadjacent portion to the bending area BA, the second protective film base171 b may be at least partially removed corresponding to the bendingarea BA, and thus, one opening or one groove corresponding to thebending area BA may be obtained.

FIG. 21 is a schematic cross-sectional view of a modified example of adisplay apparatus according to an embodiment. As shown in FIG. 21, inthe display apparatus according to the embodiment, the adhesive layer172 of the protective film 170 may include an opening 172′ correspondingto the bending area BA. In this case, the opening 172′ may be filledwith air. Otherwise, the protective film base 171 may also include anopening corresponding to the opening 172′ of the adhesive layer 172.

A part of the adhesive layer 172 of the protective layer 170 may includea plurality of openings corresponding to the bending area BA. Inaddition, when the first protective film base 171 a corresponds to thebending area BA, the adhesive layer 172 may include a plurality ofopenings corresponding to the plurality of openings 171 a′ of the firstprotective film base 171 a, as shown in FIG. 19. This may be understoodthat the first protective film base 171 a includes the plurality ofopenings 171 a′ corresponding to the plurality of openings of theadhesive layer 172.

When the adhesive layer 172 of the protective film 170 includes theplurality of openings corresponding to the bending area BA, the secondprotective film base 171 b, not the first protective film base 171 a,may correspond to the bending area BA. In this case, the adhesive layer172 may also include the plurality of openings corresponding to theplurality of openings of the second protective film base 171 b. Also,this may be understood that the second protective film base 171 bincludes the plurality of openings corresponding to the plurality ofopenings of the adhesive layer 172.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. A display apparatus comprising: a substratecomprising a display area and a peripheral area outside the displayarea; a display unit over an upper surface of the substrate tocorrespond to the display area; and a protective film comprising aprotective film base and an adhesive layer, the protective film beingattached to the lower surface of the substrate by the adhesive layer,wherein the protective film base comprises a first protective film basecorresponding at least to the display area, and a second protective filmbase having physical properties that are different from physicalproperties of the first protective film base and corresponding to atleast a part of the peripheral area.
 2. The display apparatus of claim1, wherein the second protective film base has a light transmittancethat is greater than a light transmittance of the first protective filmbase.
 3. The display apparatus of claim 1, wherein the first protectivefilm base has a thermal resistance that is greater than a thermalresistance of the second protective film base.
 4. The display apparatusof claim 3, wherein the first protective film base has a heatdeformation temperature that is higher than a heat deformationtemperature of the second protective film base.
 5. The display apparatusof claim 1, further comprising an electronic device or a printed circuitboard over the upper surface of the substrate so as to correspond to anelectronic device area included in the peripheral area, wherein thesecond protective film base corresponds at least to the electronicdevice area.
 6. The display apparatus of claim 5, wherein the secondprotective film base extends to an edge of the substrate facing awayfrom the display area.
 7. The display apparatus of claim 5, wherein afirst end portion of the first protective film base in a direction tothe electronic device area is in surface-contact with a second endportion of the second protective film base in a direction to the displayarea.
 8. The display apparatus of claim 7, wherein the first end portionand the second end portion correspond to an edge of the display area inthe direction to the electronic device area.
 9. The display apparatus ofclaim 7, wherein the first end portion and the second end portioncorrespond to an edge of the electronic device area in the direction tothe display area.
 10. The display apparatus of claim 5, wherein a firstend portion of the first protective film base in a direction to theelectronic device area corresponds to an edge of the display area in adirection to the electronic device area.
 11. The display apparatus ofclaim 5, wherein a second end portion of the second protective film basein a direction to the display area corresponds to an edge of theelectronic device area in a direction to the display area.
 12. Thedisplay apparatus of claim 5, wherein a first end portion of the firstprotective film base in a direction to the electronic device area isspaced apart from a second end portion of the second protective filmbase in a direction to the display area.
 13. The display apparatus ofclaim 12, wherein the adhesive layer comprises a first adhesive layercorresponding to the first protective film base and a second adhesivelayer corresponding to the second protective film base, and an endportion of the first adhesive layer in the direction to the electronicdevice area is spaced apart from an end portion of the second adhesivelayer in the direction to the display area.
 14. The display apparatus ofclaim 1, wherein the adhesive layer comprises a first adhesive layercorresponding to the first protective film base and a second adhesivelayer having a physical property different from a physical property ofthe first adhesive layer and corresponding to the second protective filmbase.
 15. The display apparatus of claim 1, wherein the peripheral areacomprises a bending area and the substrate is bent at the bending area.16. The display apparatus of claim 15, wherein the first protective filmbase corresponds to the bending area.
 17. The display apparatus of claim16, wherein a part of the first protective film base corresponding tothe bending area is at least partially removed.
 18. The displayapparatus of claim 16, wherein a part of the first protective film basecorresponding to the bending area comprises a plurality of openings or aplurality of grooves.
 19. The display apparatus of claim 18, whereineach of the plurality of openings or each of the plurality of groovesextends from the display area toward the peripheral area in a virtualcurved surface that is in parallel with the upper surface of thesubstrate that is bent.
 20. The display apparatus of claim 18, wherein,from among the plurality of openings or the plurality of grooves,openings or grooves locating at a center portion of the bending areahave areas that are greater than areas of openings or grooves locatingnear edges of the bending area.
 21. The display apparatus of claim 18,wherein inner side surfaces of the plurality of openings or theplurality of grooves are non-perpendicular to the upper surface of thesubstrate.
 22. The display apparatus of claim 18, wherein a portion ofthe first protective film base, wherein the portion includes theplurality of openings or the plurality of grooves, has an area that isless than an area of the bending area.
 23. The display apparatus ofclaim 18, wherein a portion of the first protective film base, whereinthe portion includes the plurality of openings or the plurality ofgrooves, has an area that is equal to an area of the bending area. 24.The display apparatus of claim 18, wherein a portion of the firstprotective film base, wherein the portion includes the plurality ofopenings or the plurality of grooves, has an area that is greater thanan area of the bending area.
 25. The display apparatus of claim 15,wherein the second protective film base corresponds to the bending areaand an adjacent portion to the bending area.
 26. The display apparatusof claim 25, wherein a part of the second protective film basecorresponding to the bending area is at least partially removed.
 27. Thedisplay apparatus of claim 25, wherein a part of the second protectivefilm base corresponding to the bending area comprises a plurality ofopenings or a plurality of grooves.
 28. The display apparatus of claim27, wherein each of the plurality of openings or each of the pluralityof grooves extends from the display area toward the peripheral area in avirtual curved surface that is in parallel with the upper surface of thesubstrate that is bent.
 29. The display apparatus of claim 27, wherein,from among the plurality of openings or the plurality of grooves,openings or grooves locating at a center portion of the bending areahave areas that are greater than areas of openings or grooves locatingnear edges of the bending area.
 30. The display apparatus of claim 15,wherein the adhesive layer comprises an opening corresponding to thebending area.
 31. The display apparatus of claim 30, wherein the openingis filled with air.
 32. The display apparatus of claim 30, wherein theprotective film base comprises an opening corresponding to the openingof the adhesive layer.
 33. The display apparatus of claim 15, whereinthe adhesive layer comprises a plurality of openings corresponding tothe bending area.
 34. The display apparatus of claim 33, wherein thefirst protective film base corresponds to the bending area, and thefirst protective film base comprises a plurality of openings or aplurality of grooves corresponding to the plurality of openings of theadhesive layer.
 35. The display apparatus of claim 33, wherein thesecond protective film base corresponds to the bending area and anadjacent portion to the bending area, and the second protective filmbase comprises a plurality of openings or a plurality of groovescorresponding to the plurality of openings of the adhesive layer.